1. Field of the Invention
This invention relates to a method of manufacturing pellets and a pellet product.
2. Prior Art
Pellets, which are used as food stuffs for animals, have been made for many years using the conventional manufacturing process comprising the steps of mixing the components of the pellet, which may include meat or fish meal, soya meal, flour or other components and normally comprise twelve to fourteen percent of water, and then feeding these components into a conditioner where they are exposed to steam which effectively starts the cooking process and increases the moisture content so that the final product had approximately sixteen to eighteen percent of water, passing the material through a pelletizing mill, which caused further heating, and then cooling and drying the prepared pellets.
This process has provided a pellet which has been fully satisfactory for use as a pellet for animals and birds, where the pellets are normally maintained substantially dry but has not necessarily been satisfactory for providing pellets for all aquaculture type of applications.
Pellets for use in aquaculture need to maintain their integrity in the water for at least a number of hours and must also be able to withstand claw attack when they are being used, for example, for feeding prawns which pick the pellets up in their claws before passing them to their mouths.
Pellets produced by the conventional process have being unsatisfactory for such applications and it is believed that the main reason for this is that the pellets are normally bound by starch, which effects its binding by changing its state during the heating in the conditioner and whilst being formed into the pellets and when the pellets are wet the starch tends to expand and this tends to cause the pellets to disintegrate.
Some pellets have used artificial binders but such pellets are still unstable for use in aquaculture.
In the aquaculture art there have been substantial difficulties with food as if the food is not eaten, then it tends to decompose and pollutes the water in which the fish are located, and it is necessary to either clean tanks and flush water therethrough, if there is a build up of decomposing food or, when ocean fish are being cultured, it is necessary to ensure that the fish cages are located in a relatively active tidal area to ensure that the decomposed food is removed.
If pellets which have a good life in water can be fed to the fish, and in this specification fish is to include crustaceans and other marine animals, then not only will there be an economy in that there can be maximum usage of the food but also the level of pollution can be substantially reduced.